The Statistics Core has five specific aims essential to achieving the Center's mission. This Core serves the Center's multifaceted needs by 1) designing and administering CEDAR's Management and Information System regulating the a) Subject Tracking Information System; b) Research Protocol Information System (collection, entry, verification, storage, scoring, backup, security and confidentiality, retrieval, processing and; disseminating of the data), and c) the Local Area Network (LAN) and CEDAR's Web Site;. 2) conducting psychometric analyses of all instruments used in CEDAR to assure their quality; 3) investigating the robustness of item response theory (IRT) methods pertinent to longitudinal family research (e.g., missing data, dependency between items, heterogeneity of the sample); 4) leading the CEDAR faculty engaged in analyses directed at confirming/disconfirming CEDAR's biopsychosocial theory of SUD etiology; and, 5) providing consultative statistical support for CEDAR faculty, fellows, and students, in addition, all statistical analyses contained, in data-based manuscripts are reviewed by this Core prior to submission for publication.